Galectin-1 and -3 in high amounts inhibit angiogenic properties of human retinal microvascular endothelial cells <em>in vitro</em>.

PURPOSE: Galectin-1 and -3 are β-galactoside binding lectins with varying effects on angiogenesis and apoptosis. Since in retinal pigment epithelial cells high amounts of human recombinant galectin (hr-GAL)1 and 3 inhibit cell adhesion, migration and proliferation, we investigated if hr-GAL1 and 3 have homologous effects on human retinal microvascular endothelial cells (HRMEC) in vitro. METHODS: To investigate the effect of galectin-1 and -3 on HRMEC, proliferation, apoptosis and viability were analyzed after incubation with 30, 60 and 120 μg/ml hr-GAL1 or 3 by BrdU-ELISA, histone-DNA complex ELISA, live/dead staining and the WST-1 assay, respectively. Further on, a cell adhesion as well as tube formation assay were performed on galectin-treated HRMEC. Migration was investigated by the scratch migration assay and time-lapse microscopy. In addition, immunohistochemical staining on HRMEC for β-catenin, galectin-1 and -3 were performed and β-catenin expression was investigated by western blot analysis. RESULTS: Incubation with hr-GAL1 or 3 lead to a decrease in proliferation, migration, adhesion and tube formation of HRMEC compared to the untreated controls. No toxic effects of hr-GAL1 and 3 on HRMEC were detected. Intriguingly, after treatment of HRMEC with hr-GAL1 or 3, an activation of the proangiogenic Wnt/β-catenin signaling pathway was observed. However, incubation of HRMEC with hr-GAL1 or 3 drew intracellular galectin-1 and -3 out of the cells, respectively. CONCLUSION: Exogenously added hr-GAL1 or 3 inhibit angiogenic properties of HRMEC in vitro, an effect that might be mediated via a loss of intracellular endogenous galectins

Immunocytochemical and ultrastructural evidence of glial cells and hyalocytes in internal limiting membrane specimens of idiopathic macular holes.

PURPOSE: To provide new information on epiretinal cell proliferation and the cells&#39; origin in idiopathic macular holes and to overcome the effects of embedding and sectioning preparation procedures on cell-distribution patterns. METHODS: Interference and phase-contrast microscopy, immunocytochemistry, and scanning and transmission electron microscopy were performed on surgically excised whole-mounted internal limiting membrane (ILM) specimens removed from 60 eyes with idiopathic macular holes. Cell distribution and cell morphology were correlated with immunocytochemical staining characteristics. Twelve cell type-specific antibodies were used to detect glial cells, hyalocytes, retinal pigment epithelial cells, retinal ganglion cells, and immune cells. Cell viability was analyzed. RESULTS: Epiretinal cell proliferation was found in all ILM specimens, irrespective of the stage of the macular hole. Cell density showed a broad variety. Immunocytochemistry frequently revealed simultaneous expression of GFAP/CD45, GFAP/CD64, GFAP/CD68, GFAP/CRALBP, and GFAP/CD90. Some cells presented with intracellular contractile filaments (anti-&alpha;SMA); others were not immunoreactive to any antibody examined. The percentage of viable cells showed a broad variety with a mean of 73% (SD 29%). Electron microscopy demonstrated glial cells, hyalocytes, and myofibroblast-like cells. CONCLUSIONS: The presence of epiretinal cells at the ILM in all macular hole stages strongly suggests a substantial involvement of cell migration and proliferation in the course of macular hole development. Glial cells and hyalocytes play the predominant role in epiretinal cell proliferation. Given the co-expression of glial cell and hyalocyte markers, transdifferentiation of epiretinal cells needs further elucidation, especially with respect to &alpha;SMA-positive cells leading to traction at the vitreoretinal interface

Ermittlung der Abwaelzwiderstaende in den Kippteilen staehlerner Punktkippgleitlager

Steel point and line rocker bearings are used in civil engineering, especially in bridge construction. Technical literature does not provide any data of the rolling-off resistance in the rocker parts of such bearings. Therefore the experimental determination of this resistance was the main objective of this research project. Using a special tilting device, tests were conducted on point rocker sliding bearings with pressure contact plates of steel St 52 and stainless steel whereby the level of loading (Hertzian stress in the contact surfaces) and the thickness' of the contact components were varied. The rolling-off resistance at rocker's maximum rotation of tan a=0.01 were calculated from the measured results and presented in diagrams. Also permanent deformations of the contact plates were measured. In addition the Hertzian formulas and the material stress' for point contact were described in more detail. Rolling-off and rolling resistance were compared using empirically derived formulas. Test results show the following: The rolling-off resistance is influenced significantly by the Hertzian stress' in the contact surfaces, the material quality, the level of preloading, plastic deformations and thickness of the contact components as well as the rotation angle. Contrary to present regulations, not only the geometric excentricity but also the rolling-off resistance should be taken into account when Hertzian stress' in the contact surface are significantly higher than those at local yielding of the contact plates. According to the present state of knowledge, the permissible Hertzian stress' given in different standards should be reduced for rocker bearings. As for roller bearings, the permissible contact pressure should be correlated with the amount of the rolling-off resistance. At the tilting angles investigated, the rolling-off resistance of rocker bearings is significantly smaller than the rolling resistance of roller bearings. The rolling-off resistance was experimentally determined for the first time with the investigations presented here. In view of the numerous factors of influence, several questions could not be answered in a complete and final manner. (orig.)SIGLEAvailable from TIB Hannover: ZA 4681(704)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Rotation, Strain, and Translation Sensors Performance Tests with Active Seismic Sources

Interest in measuring displacement gradients, such as rotation and strain, is growing in many areas of geophysical research. This results in an urgent demand for reliable and field-deployable instruments measuring these quantities. In order to further establish a high-quality standard for rotation and strain measurements in seismology, we organized a comparative sensor test experiment that took place in November 2019 at the Geophysical Observatory of the Ludwig-Maximilians University Munich in Fürstenfeldbruck, Germany. More than 24 different sensors, including three-component and single-component broadband rotational seismometers, six-component strong-motion sensors and Rotaphone systems, as well as the large ring laser gyroscopes ROMY and a Distributed Acoustic Sensing system, were involved in addition to 14 classical broadband seismometers and a 160 channel, 4.5 Hz geophone chain. The experiment consisted of two parts: during the first part, the sensors were co-located in a huddle test recording self-noise and signals from small, nearby explosions. In a second part, the sensors were distributed into the field in various array configurations recording seismic signals that were generated by small amounts of explosive and a Vibroseis truck. This paper presents details on the experimental setup and a first sensor performance comparison focusing on sensor self-noise, signal-to-noise ratios, and waveform similarities for the rotation rate sensors. Most of the sensors show a high level of coherency and waveform similarity within a narrow frequency range between 10 Hz and 20 Hz for recordings from a nearby explosion signal. Sensor as well as experiment design are critically accessed revealing the great need for reliable reference sensors.ISSN:1424-822